This is a visual symptom of an incompatible graphics card. Please check whether your system meets the minimum recommended graphic requirements using:
Try looking for a graphics card driver update through the 'Windows Device Manager' on your PC. After installing it (if available), restart your PC and launch DS Mechanical again.
If your graphics card requirements are met but you still see the 'Graphics is not available' message, try deleting this file and then starting DSM: C:\Users\"Your Windows username"\AppData\Local\SpaceClaim\SpaceClaim.exe_Url_gvqfhgv3kynzmln3sj2zsp2zsbzw0b2t\188.8.131.52\user.config